It is already known to coat a surface by a process in which a bar or rod of consumable coating material is applied with pressure against the surface to be treated while being rotated axially at a speed that generates sufficient friction at the region of contact to ensure that the coating material flows without melting so as to coat the surface. The process makes it possible to obtain a wide variety of coatings with a high integrity bond between the coating material and its substrate.
One problem arising with this process is that the quality of the surface produced is adversely affected if the coating is not formed in a continuous process, with the feed force exerted by the consumable bar on the surface being maintained at an appropriately high value until the area to be coated is finished. That is a problem because the feed-forward mechanisms used for such a rotary friction surfacing process are limited in the length of bar stock they can advance without interrupting the feed to bring a further length into use.
It is true that continuous feed arrangements as such are known for consumable welding processes, for example, in which a welding wire is fed by a pair of oppositely rotating wheels, but such a process cannot be adapted to feeding the surfacing materials for rotary friction surfacing processes because it is not possible to apply simultaneously the required high speed rotation to the feed material. Furthermore, the rods used for rotary surface treatment processes are essentially rigid and are conveniently handled in relatively short lengths, so it would be desirable also to have a feed mechanism that was able to feed a series of rods in succession without interrupting the application of the rod material under pressure to the surface being treated.